Hemodynamic effects of exercise in isolated valvular aortic stenosis.

Hemodynamic data, including simultaneously measured left ventricular and aortic pressures, were obtained from 20 patients with isolated valvular aortic stenosis at rest and during supine leg exercise. Changes in left ventricular end-diastolic pressure during exercise were not significantly related to the severity of aortic stenosis but were correlated with age; patients with abnormal left ventricular end-diastolic pressures during exercise were significantly older than those in whom this variable remained normal. Exercise resulted in significant increases in both the mean rate of systolic aortic blood flow and the mean systolic pressure gradient across the aortic valve. Analysis of this pressure gradient demonstrated symmetrical shortening of the ejection time per beat with an increase of the maximal systolic pressure gradient during exercise. Although changes in mean systolic aortic pressure gradient and mean aortic flow were significantly positively correlated, the increases in mean systolic pressure gradient during exercise were less than predicted from corresponding increases in mean aortic flow; thus the result was an apparent increase in computed aortic valve area.